This invention relates to the field of hydrolyzing triglyceride to coproduce carboxylic acids and glycerine. More particularly, it relates to hydrolyzing triglycerides with carboxylic acid moieties containing from 6 to 26 carbon atoms.
Commercially, triglycerides have been hydrolyzed to coproduce carboxylic acids and glycerine by reacting with water under conditions of high pressure and temperature (e.g. 700 psi and 250.degree. C.). This requires very expensive equipment.
Another commercial hydrolysis process for coproducing carboxylic acids and glycerine is known as the Twitchell process. This process involves mixing triglyceride with water and petroleum-alkyl benzene sulfonic acids and boiling with open steam for 36-48 hours. Discoloration, long reaction times and high steam consumption are principal disadvantages of Twitchell splitting.
Because of the disadvantages in the aforedescribed processes, consideration has been given to converting triglycerides to acids by an acidolysis reaction wherein a first carboxylic acid is reacted with glyceride ester of second carboxylic acids whereby second carboxylic acids are displaced from the glyceride ester by the first carboxylic acid. Articles by Meade et al (Journal of The American Oil Chemists' Society 39, 1-6, 1962) disclose such a process. In particular, the Meade et al articles disclose reacting triglycerides with acetic acid in the presence of strong acid catalyst promoted by a controlled amount of water (initial water contents of 0.5 to 8% were used with 2% being "near optimal") to produce carboxylic acids displaced from the triglycerides and triacetin. Under the best Meade et al conditions, 2 hours were required for a 65% yield of displaced acids, four hours for a 75% yield, eight hours for an 85% yield and 24 hours for a 90% yield. Moreover, Meade et al was aiming to produce triacetin rather than glycerine which is the usual triglyceride hydrolysis by-product. Furthermore, in Meade et al, the displacing acid (acetic acid) is a stoichiometric reactant (not a catalyst) consumed to produce triacetin.
It is an object of this invention to provide hydrolysis of said triglycerides wherein relatively mild conditions of temperature and pressure can be used (enabling the use of relatively inexpensive processing equipment) to coproduce high yields of displaced carboxylic acids and glycerine in relatively short times (e.g. greater than 75% conversion in less than one hour).
It is a further object of this invention to provide a process wherein displacing acid is not consumed.